Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, openWorldHint=true, and non-idempotence, so the safety posture is known without the description. The description adds only that effects and durations are constrained by workspace controls, and says nothing about whether generation is synchronous, whether an existing photo is consumed or preserved, or how results are retrieved — notable gaps for a destructive, open-world generator.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the triggering condition, with no filler. The second sentence largely restates the duration constraint already encoded in the schema, which is the only wasted clause.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need no prose, and the input schema is fully documented. However, for an asynchronous, destructive, open-world video generator sitting beside a get_generation sibling, the description gives no hint about polling for completion or about cost/irreversibility, leaving a meaningful workflow gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so every parameter is already documented in the schema, which sets the baseline at 3. The description adds marginal framing — that duration is 5 or 10 seconds and that the effect should mirror the user's wording — but nothing about the image vs image_url choice that the schema does not already explain.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a concrete verb and resource — animating a single room photo with a camera move or described effect — which is specific and distinguishable in scope. It implies the single-room boundary that separates it from create_house_tour, but never names that sibling, so an agent must infer the split.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

"Use when the user wants one room photo animated" gives a usable trigger condition, but there are no exclusions or named alternatives despite several plausible siblings (create_house_tour, create_video_transition, upscale_room_image). The agent must infer which tool wins when the request is ambiguous.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.